In semiconductor devices, strain engineering has been applied to improve electron/hole mobility.
A contemporary method for forming stressors inside a semiconductor material usually requires an ion implantation mask, which further requires a photolithography process, so as to control lateral locations of stressors to be formed. In such a method, individual, independent control of the stressors including the relative locations, depths, sizes, and doped concentrations thereof are not available, because the stressors are formed simultaneously by the same implantation.